fp-ts-task-either

TaskEither combines the laziness of Task with the error handling of Either, providing a powerful abstraction for async operations that can fail.

| Create success | TE.right(value) | Wrap value in Right | | Create failure | TE.left(error) | Wrap error in Left | | From Promise | TE.tryCatch(promise, onError) | Convert Promise to TE | | Transform value | TE.map(f) | Apply f to success value | | Transform error | TE.mapLeft(f) | Apply f to error value |

| Chain operations | TE.chain(f) / TE.flatMap(f) | Sequence dependent operations | | Recover from error | TE.orElse(f) | Try alternative on error | | Handle both cases | TE.fold(onError, onSuccess) | Pattern match result | | Parallel array | TE.traverseArray(f) | Map + sequence in parallel |